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Fracture characterization of fractured rock bodies based on acoustic and optical characteristics 基于声学和光学特征的断裂岩体断裂特征描述
IF 2.9 3区 地球科学
Frontiers in Earth Science Pub Date : 2024-08-28 DOI: 10.3389/feart.2024.1421355
Jiyong Zhang, Qianjin Zou, Huadong Guan
{"title":"Fracture characterization of fractured rock bodies based on acoustic and optical characteristics","authors":"Jiyong Zhang, Qianjin Zou, Huadong Guan","doi":"10.3389/feart.2024.1421355","DOIUrl":"https://doi.org/10.3389/feart.2024.1421355","url":null,"abstract":"Crack propagation is an important cause of damage to rock bodies. In this study, uniaxial compression tests were conducted on specimens with rock-like mass containing fissures with different inclination angles to study the effect of crack angle on the crack evolution and fracture characteristics of rock bodies. The specimen surface deformation and internal response characteristics during fracture were analyzed via digital image correlation (DIC) and acoustic emission (AE) techniques. The results indicated that the AE characteristics of the fractured specimens exhibited a high degree of activity during the pore compaction and crack propagation stages. The prefabricated fissure configuration affected the stress state at the fissure tip, leading to differences in the crack evolution paths and rupture modes of fissure specimens with different angles. Under the uniaxial peak intensity, the relative position of the normalized global strain curve peak point gradually shifted from the specimen tip to the middle of the specimen as the crack angle increased, which corresponded to the shear damage-tension-shear mixed damage-tension damage modes of the specimen. The findings of this study indicate that normalized global strain curves can reflect the characteristics of crack evolution and provide a basis for the discrimination of fissured rock mass damage modes.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"113 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Frontiers | Construction and application of multi-scale costal bedrock urban 3D engineering geological models in Qingdao City of China 前沿 | 中国青岛市多尺度造价基岩城市三维工程地质模型的构建与应用
IF 2.9 3区 地球科学
Frontiers in Earth Science Pub Date : 2024-08-28 DOI: 10.3389/feart.2024.1435824
Dong Ji, Jing Hou, Zhiliang Cheng, Shuai Wei, Yue Zhai, Wenhao Li
{"title":"Frontiers | Construction and application of multi-scale costal bedrock urban 3D engineering geological models in Qingdao City of China","authors":"Dong Ji, Jing Hou, Zhiliang Cheng, Shuai Wei, Yue Zhai, Wenhao Li","doi":"10.3389/feart.2024.1435824","DOIUrl":"https://doi.org/10.3389/feart.2024.1435824","url":null,"abstract":"The 3D geological model serves as a cornerstone, establishing the essential foundation and prerequisite for numerical simulations, analytical assessments, and evaluative procedures that are integral to the disciplines of geotechnical and geological engineering. The task of integrating vast quantities of multi-source, heterogeneous modeling data, the absence of stratigraphic division standards to meet varying precision requirements, and addressing the application demands of 3D geological models beyond the geological domain, pose significant challenges to the endeavor of 3D geological modeling. This is especially true for the construction of large-scale, high-precision 3D geological models at the urban level. Our research introduces a methodology for 3D geological modelling, with a particular focus on the dual-weighted interpolation technique for the integration of land-sea data and the establishment of a three-tiered coding system for bedrock layers. Focusing on Qingdao, a city characterized by its bedrock geology and situated along the eastern coastal region of China, our proposed method has successfully catalyzed the creation of models across four distinct scales: a comprehensive city-wide model covering an area of 11,282 square kilometers, five general models, two demonstration models, and five refined models. Further application cases have demonstrated that these models are not only capable of meeting the requirements of geological and geotechnical engineering across various scenarios, but also exhibit excellent interoperability and significant application potential when integrated with Building Information Modeling (BIM), Geographic Information Systems (GIS), and Internet of Things (IoT) technologies. The outcomes of this study are significant for the theoretical development and technological advancement of 3D geological modeling, and can also bring inspiration and reference to the work of 3D geological modeling in other areas.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"54 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Frontiers | .1.1 Late Holocene hydrologic variability and ecosystem structure from rock hyrax middens in Dhofar, Oman 前沿 | .1.1 从阿曼佐法尔(Dhofar)的岩鬣狗穴看全新世晚期的水文变异性和生态系统结构
IF 2.9 3区 地球科学
Frontiers in Earth Science Pub Date : 2024-08-28 DOI: 10.3389/feart.2024.1441323
Kaitlyn E. Horisk, Sarah Ivory, Katherine Freeman, Allison Baczynski, Joy McCorriston, Andrew Anderson, R Scott Anderson, Ali Al Kathiri
{"title":"Frontiers | .1.1 Late Holocene hydrologic variability and ecosystem structure from rock hyrax middens in Dhofar, Oman","authors":"Kaitlyn E. Horisk, Sarah Ivory, Katherine Freeman, Allison Baczynski, Joy McCorriston, Andrew Anderson, R Scott Anderson, Ali Al Kathiri","doi":"10.3389/feart.2024.1441323","DOIUrl":"https://doi.org/10.3389/feart.2024.1441323","url":null,"abstract":"Over 1/3 of the Earth’s human population relies on dryland ecosystems for food and water resources. While these ecosystems are highly sensitive to changes in climate, we lack observational data as to how changes in hydrology influences plant communities. Paleoecological data for southern Arabia show woodland communities transitioned to more dry-adapted herbaceous plants, which suggests rainfall decreased across the Holocene. To assess relationships between hydrology and ecology, we employed leaf wax n-alkane distributions, δ13Cwax, and δDwax records from rock hyrax (Procavia capensis) middens in Dhofar, Oman. The biomarker properties allowed reconstruction of changes in C3/C4 vegetation and local moisture availability, in tandem with community changes represented by a published pollen record. To constrain interpretations, n-alkane analyses were conducted on herbarium specimens of leaves collected in Dhofar. For the modern specimens, xeric plants typically contained longer homologues than mesic plants. Across the fossil middens (4,038–109 cal yrs BP), the proportions of plant-wax homologues do not show major changes, and thus do not suggest a shift between xeric versus mesic plants. Similarly, δ13Cwax values indicate little or no change in the distributions of C3 and C4 vegetation. Limited δDwax data from the middens confirm overall drying occurred into the late Holocene, punctuated by a wetter pulse at ∼1.6 ka. Taken together, plant wax distributions and isotope data indicate changes in moisture availability across the late Holocene did not alter the structural composition of the plant communities and that the proportion of C3/C4 vegetation remained stable. We infer vegetation changes associated with late Holocene drying involved reshuffling of community composition and not major changes in vegetation structure. Additionally, this study demonstrates that leaf wax n-alkanes from rock hyrax middens provide a method to reconstruct changes in climate and vegetation in dryland ecosystems where other archives are scarce.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"19 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Frontiers | Comprehensive study on the stability and failure mechanism of landslides under rainfall and earthquake in northwest mountainous areas 前沿 | 西北山区降雨和地震作用下滑坡稳定性和破坏机理的综合研究
IF 2.9 3区 地球科学
Frontiers in Earth Science Pub Date : 2024-08-27 DOI: 10.3389/feart.2024.1470083
Weixin Yang, Yonggang Zhang, Lei Zhang, Gexue Bai, Baofeng Wan, Ning An
{"title":"Frontiers | Comprehensive study on the stability and failure mechanism of landslides under rainfall and earthquake in northwest mountainous areas","authors":"Weixin Yang, Yonggang Zhang, Lei Zhang, Gexue Bai, Baofeng Wan, Ning An","doi":"10.3389/feart.2024.1470083","DOIUrl":"https://doi.org/10.3389/feart.2024.1470083","url":null,"abstract":"Landslides and geological disasters occur frequently in the mountainous areas of northwest China, seriously threatening people’s life and property of the region. In this study, we investigated the Lijie Beishan landslide as a typical case and combines the results of on-site geological surveys to conduct two-dimensional and three-dimensional numerical simulations of the landslide, evaluating its stability under self-weight, rainfall, and earthquake action. By analyzing the generalized shear strain, displacement, and stability coefficient of the landslide, it is determined that the stability of the landslide shows a decreasing trend under static, rainfall, and earthquake conditions. Landslides exhibit tension controlled failure modes under normal static and rainfall conditions, and translational failure modes under earthquake conditions. Compared with static and rainfall conditions, landslides have the largest volume and sliding distance under earthquake conditions. By combining the transfer coefficient method and the simplified Bishop method, a comparative analysis was conducted on the stability of the landslide. It was found that the stability coefficients under different working conditions were consistent with the simulation results, which verified the reliability of the simulation results. The research results of this paper will assist in clarifying the development mechanism of this type of landslides and provide valuable references for the stability evaluation of landslides in the northwest mountainous areas.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"17 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Investigating the internal erosion behavior and microscopic mechanisms of chemically stabilized soil: an experimental study 调查化学稳定土壤的内部侵蚀行为和微观机制:一项实验研究
IF 2.9 3区 地球科学
Frontiers in Earth Science Pub Date : 2024-08-27 DOI: 10.3389/feart.2024.1452449
Buping Zhang, Xinghua Zhu, Xuewen Tao, Mengkui Wang, Aamir Asghar, Guoliang Mi
{"title":"Investigating the internal erosion behavior and microscopic mechanisms of chemically stabilized soil: an experimental study","authors":"Buping Zhang, Xinghua Zhu, Xuewen Tao, Mengkui Wang, Aamir Asghar, Guoliang Mi","doi":"10.3389/feart.2024.1452449","DOIUrl":"https://doi.org/10.3389/feart.2024.1452449","url":null,"abstract":"IntroductionInternal erosion triggered by water pipeline leaks seriously threatens the stability of the urban ground. Hangzhou, a city in Zhejiang Province, China, is facing critical challenges due to urban ground collapse (UGC) caused by internal erosion. However, there is a lack of research on the prevention of UGC by improving the internal erodibility of underground soil. Addressing this issue is of utmost importance to ensure the city’s stability and safety. This paper proposes to improve the internal erodibility of typical sandy silt soils with chemical stabilisers.MethodsThe effects of three chemical stabilisers, lignosulphonate (LS), lime (LI), and lignin fibre (LF), on the critical shear stress (<jats:italic>τ</jats:italic><jats:sub>c</jats:sub>) and erosion coefficient (<jats:italic>k</jats:italic><jats:sub>d</jats:sub>) of sandy silt soils were investigated, which from Hangzhou, Zhejiang, China, by the hole erosion test (HET) at different mixing amounts and at different conservation times.ResultsThe findings indicate that LF mainly improves the erosion resistance of sandy silt by increasing <jats:italic>τ</jats:italic><jats:sub>c</jats:sub>, and the maximum increase is 2.38 times; LI mainly improves the erosion resistance by decreasing <jats:italic>k</jats:italic><jats:sub>d</jats:sub>, and the maximum decrease is 2.18 times. After adding LS, <jats:italic>τ</jats:italic><jats:sub>c</jats:sub> and <jats:italic>k</jats:italic><jats:sub>d</jats:sub> did not change significantly. The scanning electron microscope (SEM) test revealed that the inclusion of LF led to the formation of larger agglomerates in the sandy silt soil. The microstructure of sandy silt soil remained dispersed even after adding LS. Various chemical stabilisers used to improve sandy silt soils exhibited distinct erosion mechanisms. Sandy silt soils improved with LF exfoliated into agglomerates, displaying high resistance to erosion. On the other hand, the sandy silt treated with LF still lacks a protective layer and shows minimal improvements in its ability to withstand erosion. In contrast, the LS-amended sandy silt remains stripped with individual soil particles with insignificant changes in erosion resistance.DiscussionThis study can provide a conceptual framework for choosing foundation treatment techniques in future urban development projects.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"61 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Comprehensive database of land subsidence in 143 major coastal cities around the world: overview of issues, causes, and future challenges 全球 143 个主要沿海城市土地沉降综合数据库:问题、原因和未来挑战概述
IF 2.9 3区 地球科学
Frontiers in Earth Science Pub Date : 2024-08-27 DOI: 10.3389/feart.2024.1351581
Laura Pedretti, Alessia Giarola, Mandy Korff, John Lambert, Claudia Meisina
{"title":"Comprehensive database of land subsidence in 143 major coastal cities around the world: overview of issues, causes, and future challenges","authors":"Laura Pedretti, Alessia Giarola, Mandy Korff, John Lambert, Claudia Meisina","doi":"10.3389/feart.2024.1351581","DOIUrl":"https://doi.org/10.3389/feart.2024.1351581","url":null,"abstract":"Subsidence refers to the gradual lowering or sudden sinking of the ground surface and is known to impact human lives in terms of damages to the infrastructures, utility lines, and buildings as well as changes in the surficial drainage systems and groundwater conditions. The impacts of land subsidence will be greater in the future, considering the sea level rise, population growth, intensification of coastal erosion and extreme events, as well as increase in flood risk or freshwater salinization, mostly in coastal cities. The main aim of this work is to provide an open-source, peer-reviewed, and comprehensive database identifying the main and secondary causes of land subsidence in 143 coastal cities. We highlight the potential impacts of subsidence that are still unknown in some at-risk cities and non-existence of mitigation measures. The database additionally shows that mitigation measures, specifically those addressing subsidence due to groundwater extraction, have proven successful in the past. The proposed database aims to increase the knowledge on the subsidence phenomenon and also global awareness of land subsidence issues among researchers, the scientific community, stakeholders, and policymakers in terms of urban planning and development.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"40 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Deep-learning-based natural fracture identification method through seismic multi-attribute data: a case study from the Bozi-Dabei area of the Kuqa Basin, China 基于深度学习的地震多属性数据天然断裂识别方法:中国库车盆地博孜-大北地区案例研究
IF 2.9 3区 地球科学
Frontiers in Earth Science Pub Date : 2024-08-26 DOI: 10.3389/feart.2024.1468997
Yongliang Tang, Dong Chen, Hucheng Deng, Fenglai Yang, Haiyan Ding, Yuyong Yang, Cuili Wang, Xiaofei Hu, Naidong Chen, Chuan Luo, Ming Tang, Yu Du
{"title":"Deep-learning-based natural fracture identification method through seismic multi-attribute data: a case study from the Bozi-Dabei area of the Kuqa Basin, China","authors":"Yongliang Tang, Dong Chen, Hucheng Deng, Fenglai Yang, Haiyan Ding, Yuyong Yang, Cuili Wang, Xiaofei Hu, Naidong Chen, Chuan Luo, Ming Tang, Yu Du","doi":"10.3389/feart.2024.1468997","DOIUrl":"https://doi.org/10.3389/feart.2024.1468997","url":null,"abstract":"Fractures play a crucial role in tight sandstone gas reservoirs with low permeability and low effective porosity. If open, they not only significantly increase the permeability of the reservoir but also serve as channels connecting the storage space. Among numerous fracture identification methods, seismic data provide unique advantages for fracture identification owing to the provision of three-dimensional information between wells. How to accurately identify the development of fractures in geological bodies between wells using seismic data is a major challenge. In this study, a tight sandstone gas reservoir in the Kuqa Basin (China) was used as an example for identifying reservoir fractures using deep-learning-based method. First, a feasibility analysis is necessary. Intersection analysis between the fracture density and seismic attributes (the characteristics of frequency, amplitude, phase, and other aspects of seismic signals) indicates that there is a correlation between the two when the fracture density exceeds a certain degree. The development of fractures is closely related to the lithology and structure, indirectly affecting differences in seismic attributes. This indicates that the use of seismic attributes for fracture identification is feasible and reasonable. Subsequently, the effective fracture density data obtained from imaging logging were used as label data, and the optimized seismic attribute near the well data were used as feature data to construct a fracture identification sample dataset. Based on a feed-forward neural network algorithm combined with natural fracture density and effectiveness control factor constraints, a trained identification model was obtained. The identification model was applied to seismic multi-attribute data for the entire work area. Finally, the accuracy of the results from the training, testing, and validation datasets were used to determine the effectiveness of the method. The relationship between the fracture identification results and the location of the fractures in the target reservoir was used to determine the reasonableness of the results. The results indicate that there is a certain relationship between multiple seismic attributes and fracture development, which can be established using deep learning models. Furthermore, the deep-learning-based seismic data fracture identification method can effectively identify fractures in the three-dimensional space of reservoirs.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"55 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A depleted mantle source for Neoproterozoic continental rifting in the Seve Nappe Complex, Kebnekaise region, northern Swedish Caledonides 瑞典喀里多尼亚山脉北部凯布奈凯斯地区塞夫岩层群中新近纪大陆漂移的贫化地幔源
IF 2.9 3区 地球科学
Frontiers in Earth Science Pub Date : 2024-08-26 DOI: 10.3389/feart.2024.1426525
Riccardo Callegari, Abigail K. Barker, Christopher J. Barnes, Katarzyna Walczak, Grzegorz Ziemniak, Iwona Klonowska, Ellen Kooijman, Sabine Rousku, Karolina Kośmińska, Jarosław Majka
{"title":"A depleted mantle source for Neoproterozoic continental rifting in the Seve Nappe Complex, Kebnekaise region, northern Swedish Caledonides","authors":"Riccardo Callegari, Abigail K. Barker, Christopher J. Barnes, Katarzyna Walczak, Grzegorz Ziemniak, Iwona Klonowska, Ellen Kooijman, Sabine Rousku, Karolina Kośmińska, Jarosław Majka","doi":"10.3389/feart.2024.1426525","DOIUrl":"https://doi.org/10.3389/feart.2024.1426525","url":null,"abstract":"The Central Iapetus Magmatic Province (CIMP) is a large igneous province (LIP) emplaced in the Baltican and Laurentian paleocontinents that marks the onset of the Caledonian Wilson Cycle. Paleozoic magmatism of the CIMP is preserved in both northeastern America and northern Europe. This study investigates rocks belonging to the hyper-extended margin of Baltica currently found in the Seve Nappe Complex of the Scandinavian Caledonides. Specifically, U-Pb zircon geochronology and whole-rock geochemistry are applied to a migmatitic variety of the Vierručohkka amphibolite of the Mårma Terrane, to the Aurek gabbro, and amphibolite of the Aurek Assemblage exposed in the Seve Nappe Complex in the Kebnekaise region, northern Swedish Caledonides. U-Pb zircon geochronology yields crystallization ages of 626 ± 7 Ma for the protolith of the Vierručohkka amphibolite, and 614 ± 2 Ma and 609 ± 1 Ma for the emplacement of the Aurek gabbro and amphibolite protolith, respectively. A younger age of 599 ± 3 Ma is recorded in the Vierručohkka amphibolite and is interpreted as the age of partial melting and migmatization. The geochemical signatures of the rocks demonstrate crustal assimilation during the emplacement of their protoliths and modification due to prograde metamorphic processes during Caledonian subduction. The Vierručohkka amphibolite and the Aurek Assemblage samples display upper and lower crustal assimilation, respectively. Trace elements (Dy, Sm, Lu, and Y) record the growth of metamorphic garnet, while elevated TiO<jats:sub>2</jats:sub> contents record the crystallization of metamorphic rutile. Nevertheless, high field strength elements (HSFE) and ∆Nb suggest a depleted mantle source for the magmas of the protoliths of the investigated rocks. Altogether, geochemical data indicate that the igneous activity recorded in the Vierručohkka amphibolite and the Aurek Assemblage between c. 626–609 Ma is related to continental rifting processes associated with the opening of the Iapetus Ocean.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"47 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Experimental study on dynamic interaction between ground fissure and diagonal three-section subway tunnels 地裂缝与对角线三截面地铁隧道之间动态相互作用的试验研究
IF 2.9 3区 地球科学
Frontiers in Earth Science Pub Date : 2024-08-23 DOI: 10.3389/feart.2024.1453210
Lei Liu, Zhilin Ren, Weiheng Peng, Jinkai Yan
{"title":"Experimental study on dynamic interaction between ground fissure and diagonal three-section subway tunnels","authors":"Lei Liu, Zhilin Ren, Weiheng Peng, Jinkai Yan","doi":"10.3389/feart.2024.1453210","DOIUrl":"https://doi.org/10.3389/feart.2024.1453210","url":null,"abstract":"Ground fissures, as a typical geohazard, pose potential georisks to the construction and maintenance of urban transportation infrastructure. Under the influence of ground fissures, the segmented tunnel structure used in subway systems complicates the propagation of subway train vibrations. In this study, the soil acceleration, earth pressure and contact pressure of a three-section subway tunnel under dynamic loading of a subway train in a ground fissure environment were observed and analyzed by physical modeling tests, and the effects of the presence and activity of the ground fissure and tunnel segmentation were discussed. The results show that the vibration generated by the subway traveling will have different degrees of attenuation when propagating in all directions in the soil layer, and the ground fissure has a damping effect on the subway vibration. The attenuation and enhancement of acceleration by ground fissure is affected by the activity and propagation direction of ground fissure. The distribution of additional earth pressure is affected by the ground fissure, soil contact state, which is related to the ground fissure activity state. The ground fissure activity on the contact additional pressure mainly focuses on the bottom and top of the tunnel and there are differences in the location of the hanging wall and footwall. Three-section tunnels have a stronger vibration response and vibration attenuation than monolithic tunnels due to the influence of segmentation. Based on the consideration of the effects of ground fissure and tunnel segmentation, the tunnel design mainly takes into account the amount of ground fissure activity and determines the structural measures, the tunnel structure at the location of the ground fissure is strengthened, in addition to the vibration attenuation measures for the segmented tunnels when crossing the ground fissure. The discussion of mechanical response and design measures in this study helps to reduce the georisk of ground fissures on urban underground transportation infrastructure.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"139 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Understanding the spatio-temporal behaviour of riverine plastic transport and its significance for flux determination: insights from direct measurements in the Austrian Danube River 了解河流塑料迁移的时空行为及其对通量确定的意义:奥地利多瑙河直接测量的启示
IF 2.9 3区 地球科学
Frontiers in Earth Science Pub Date : 2024-08-22 DOI: 10.3389/feart.2024.1426158
Sebastian Pessenlehner, Philipp Gmeiner, Helmut Habersack, Marcel Liedermann
{"title":"Understanding the spatio-temporal behaviour of riverine plastic transport and its significance for flux determination: insights from direct measurements in the Austrian Danube River","authors":"Sebastian Pessenlehner, Philipp Gmeiner, Helmut Habersack, Marcel Liedermann","doi":"10.3389/feart.2024.1426158","DOIUrl":"https://doi.org/10.3389/feart.2024.1426158","url":null,"abstract":"Plastic pollution in aquatic environments is a growing concern, with rivers recognized as major pathways. However, rivers themselves are also subject to pollution. Hence, understanding riverine plastic transport dynamics is essential for mitigating environmental impacts. Although plastic-related research focus has shifted from marine environments towards rivers, challenges remain in standardizing methods for monitoring and integrating spatio-temporal variabilities of riverine plastic occurrence into flux determination. This study addresses these challenges by adopting established methods from sediment research. Utilizing data from a net-based cross-sectional multi-point approach, it examines spatio-temporal and discharge-dependent variations. It comprehensively analyzes the complex dynamics of plastic transport in the Danube River, contrasting an impounded section near Aschach, Austria, with a free-flowing reach near Hainburg, Austria. The paper emphasizes the significance of applying these methodologies for accurate flux determination and underscores the risks of neglecting them. By incorporating average microplastic particle weights, we aim to overcome limitations in prior methodologies that solely emphasize qualitative aspects or rely on item numbers. Spatial distribution analysis revealed a pronounced stratification at low flow and a more variable distribution in the free-flowing section, attributed to higher turbulence. As discharge increased, vertical mixing occurred, along with distinct lateral patterns displaying increased concentrations toward the riverbanks. Encountering plastic particles throughout the river profile underscores their properties of both suspended and floating matter, emphasizing the importance of hydro-morphology and multi-point cross-sectional measurement approaches. Microplastic loads were calculated to be &amp;lt;6.9 t a<jats:sup>−1</jats:sup> in Aschach and &amp;lt;17.1 t a<jats:sup>−1</jats:sup> in Hainburg, compared to total plastic loads of &amp;lt;14.3 t a<jats:sup>−1</jats:sup> in Aschach and &amp;lt;41.6 t a<jats:sup>−1</jats:sup> in Hainburg. Consequently, plastic loads were doubled to tripled within the Austrian section of the Danube River. The study contributes valuable insights into the complex nature of plastic transport in river systems, emphasizing comprehensive spatial, temporal and discharge-dependent assessments for characterizing and managing plastic pollution. It suggests that rivers can function as sources, pathways and sinks of plastic pollution, contingent upon hydro-morphological conditions. This underscores the need for longitudinal, basin-wide assessments to accurately understand plastic transport dynamics.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"82 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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